Ovarian Cancer (OC) and its management
Ovarian cancer is the second most common gynaecological cancer in the western world, and the leading cause of death from gynaecological malignancies [Dinh 2008]. Its estimated crude incidence in the European Union is close to 18/100,000 women/year and the mortality reaches 12/100,000 women/year [Vasey 2005]. Approximately 30,000 women die annually from ovarian cancer in Europe [Ferlay 2002]. Most of these cases affect women older than 50 years, and epithelial tumours account for over 90% of all ovarian cancers [Salzberg 2005; Colombo 2006].
Staging is described using the American Joint Committee on Cancer (AJCC) and the Federation Internationale de Gynecologie et d’Obstetrique (FIGO) classification guidelines (Table 1).
The mortality rate of ovarian cancer has slightly changed within the last 50 years, and long-term trends in cancer mortality reveal few encouraging advances in overall survival, possibly favoured by improved surgery and the use of new active drugs [Ferlay 2002].
Surgery can be curative when the disease is still confined to the ovary, and in these cases 5-year survival rates exceed 90%. However, as most patients present with intraperitoneal dissemination, survival rates drop to 20-25% [Ozols 2005]. Current standard primary therapy for advanced ovarian cancer involves maximal cytoreductive surgery followed by systemic platinum-based chemotherapy -usually carboplatin- combined with a taxane [Ozols 2005; Salzberg 2005; Colombo 2006; du Bois 2005]. Up to 80% of women with stage III/IV tumours respond to therapy, and 50% achieve a complete response. Despite these high initial response rates, results still remain far from satisfactory, as median time to progression (TTP) does not exceed 15-18 months, median survival is below 3 years, and 5-year survival rates are close to 30% [Vermorken 2008]. Furthermore, a large proportion of responding patients (50-75%) eventually relapse [Vermorken 2008].
Table 1. American Joint Committee on Cancer (AJCC) TNM and FIGO Staging System for Ovarian and Primary Peritoneal Cancer (7th ed., 2010)
|Primary Tumour (T)|
|TX||Primary tumour cannot be assessed||T3||III||Tumour involves one or both ovaries with microscopically confirmed peritoneal metastasis outside the pelvis|
|T0||No evidence of primary tumour||T3a||IIIA||Microscopic peritoneal metastasis beyond pelvis (no macroscopic tumour)|
|T1||I||Tumour limited to ovaries (one or both)||T3b||IIIB||Microscopic peritoneal metastasis beyond pelvis 2 cm or less in greatest dimension|
|T1a||IA||Tumour limited to one ovary; capsule intact, no tumour on ovarian surface. No malignant cells in ascites or peritoneal washings||T3c||IIIC||Peritoneal metastasis beyond pelvis more 2 cm in greatest dimension and/or regional lymph node metastasis|
|T1b||IB||Tumour limited to both ovaries; capsules intact, no tumour on ovarian surface. No malignant cells in ascites or peritoneal washings||Regional Lymph Nodes (N)|
|T1c||IC||Tumour limited to one or both ovaries with any of the following: capsule ruptured, tumour on ovarian surface, malignant cells in ascites or peritoneal washings||NX||Regional lymph nodes cannot be assessed|
|T2||II||Tumour involves one or both ovaries with pelvic extension||N0||No regional lymph node metastasis|
|T2a||IIA||Extension and/or implants on uterus and/or tube(s). No malignant cells in ascites or peritoneal washings||N1||IIIC||Regional lymph node metastasis|
|T2b||IIB||Extension to and/or implants on other pelvic tissues. No malignant cells in ascites or peritoneal washings||Distant Metastasis (M)|
|T2c||IIC||Pelvic extension and/or implants (T2a or T2b) with malignant cells in ascites or peritoneal washings||M0||No distant metastasis|
|M1||IV||Distant metastasis (excludes peritoneal metastasis)|
|Note: Liver capsule metastasis is T3/Stage III; liver parenchymal metastasis, M1/Stage IV. Pleural effusion must have positive cytology for M1/Stage IV.|